Head-up displays (HUDs) are being developed as automotive display devices to project display information such as destination navigation information and the like onto a windshield to allow simultaneous visual confirmation of the external environment information and the display information. Although the display of the HUD is viewed with both eyes in the case of a normal HUD, binocular parallax occurs and the display is difficult to view.
Conversely, a monocular HUD has been proposed in which the display is viewed with one eye (for example, refer to JP-A 2009-128565 (Kokai)). According to such a monocular HUD, a virtual image of the display object can be perceived at a spatial position that is matched to the background.
In such a monocular HUD, it is desirable for the depthward position at which the display object is disposed to match the perceived depthward position at which the display object is actually perceived with even higher precision.